Fiji

Tropical Cyclone Winston - Estimated Impacts Warning 29, 20 February 2016 0900 UTC

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[JTWC] Summary: TROPICAL CYCLONE (TC) 11P (WINSTON), LOCATED APPROXIMATELY 45 NM NORTH-NORTHEAST OF SUVA, FIJI, HAS TRACKED WESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. TC WINSTON IS EXPECTED TO CONTINUE TRACKING WESTWARD THROUGH TAU 36. THE CYCLONE WILL WEAKEN SLIGHTLY AS IT PASSES THROUGH THE ISLAND CHAIN DUE TO LAND INTERACTION. HOWEVER, THE AFOREMENTIONED FAVORABLE ENVIRONMENTAL CONDITIONS WILL SUPPORT ANOTHER INTENSIFICATION AS THE CYCLONE MOVES AWAY FROM THE ISLANDS OVER SSTS NEAR 31 CELSIUS. CONCURRENTLY, THE STEERING STR WILL RETROGRADE TO THE WEST ALLOWING A SECONDARY RIDGE TO BUILD IN JUST EAST OF THE SYSTEM. THE COMBINED EFFECTS WILL ALLOW TC WINSTON TO TURN POLEWARD ALONG THE WESTERN PERIPHERY OF THE STR TO THE EAST. NEAR TAU 48, TC 11P WILL REACH A SECONDARY MAXIMUM INTENSITY OF 140 KNOTS DUE TO AN ENHANCED POLEWARD OUTFLOW CHANNEL CAUSED BY AN APPROACHING UPPER LEVEL TROUGH. AFTERWARDS, AS THE CYCLONE MOVES FURTHER POLEWARD, IT WILL ENCOUNTER MODERATE TO HIGH VWS AND RAPIDLY DECREASING SSTS. THESE DEGRADED ENVIRONMENTAL CONDITIONS WILL BEGIN THE FINAL WEAKENING TREND. IN THE EXTENDED FORECAST, AS THE CYCLONE NEARS TROPICAL STORM INTENSITY, A LOW TO MID-LEVEL STR LOCATED TO THE SOUTH WILL FORCE THE SYSTEM WESTWARD ONCE AGAIN. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT AS THE SYSTEM TRACKS WESTWARD; HOWEVER, THERE CONTINUES TO BE A LARGE SPREAD IN THE TIMING OF THE POLEWARD TURN. ALTHOUGH MODEL GUIDANCE SUPPORTS HIGH CONFIDENCE IN THE NEAR TERM, THE LACK OF MODEL AGREEMENT BEYOND TAU 24 LENDS LOW CONFIDENCE TO THE OVERALL JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 200600Z IS 40 FEET